1. Field of the Invention
This invention relates to the field of medical casting and splinting devices. More specifically it relates to those devices which maintain a dry exterior surface.
2. Description of the Related Art
Casts and splints have traditionally been made by coating or impregnating a substrate, usually fabric, such as gauze, mesh, fiberglass or the like with a dry casting material such as plaster of Paris or various resins. The coated substrate is then dipped in water, to initiate the "setting" of the casting material; squeezed or wrung out to express excess water; placed on the appropriate part of the patient; and allowed to dry or "cure."
This process is often very messy, time consuming, requires multiple supplies, and considerable skill. Wet casting material gets on everything from hands, clothes, patient, floor, furniture and the like. Usually the person applying the cast or splint wears gloves and protective clothes and often uses a special "casting" room. If colored compounds are used messy stains may result, and if resins are used, a detackifier may be necessary. Often, a protective layer of material is placed on the patient to protect the skin (see U.S. Pat. No. 4,193,395, which covers the body part with stockinette).
Some casting devices have been described (U.S. Pat. Nos. 4,235,228, 4,442,833, 4,454,874, 4,628,917, 4,770,299, 4,869,046, 4,899,738) which enclose the casting material in sleeves or coverings of various materials so that direct contact with the casting material is not necessary.
Even those devices that enclose the casting material still require immersing the device in water, wringing, and applying. This results in a wet layer of material in direct contact with the patient's skin, which may be uncomfortable and irritating and can, in time, cause maceration and sloughing of the skin. This also requires a ready source of water, which may not be available in some circumstances.
Some devices have tried placing a totally moisture impervious layer next to the skin (U.S. Pat. No. 4,454,874). This may keep moisture from the casting material from contacting the skin. However, it traps moisture that is normally released from the skin in sweating and respiration of the skin, and this builds up under the impervious layer and may cause tissue damage, odor and the like. Other, non-unitary, devices have used a separate dry pad or layer to be applied to the patient or adhered to the casting device after the casting device or material is wetted (U.S. Pat. Nos. 4,193,395 and 4,628,917). These latter devices require more than one component, and adhesives usually do not hold well in a moist environment and may restrict respiration of vapor.
Other devices have been described which use hydrophobic material on the patient contact side, but which still require immersing the device. The immersion and "squeezing" of the device results in water being trapped or retained in the spaces of the hydrophobic material which then presents a wet surface to the patient and may trap moisture next to the patient (U.S. Pat. Nos. 4,770,299, 4,869,046, 4,899,738).